The present invention relates to a head arm assembly (HAA) configured by assembling at least one head gimbal assembly (HGA) with at least one head element such as a thin-film magnetic head element or an optical head element and at least one movable arm or actuator arm for supporting the at least one HGA, to a disk apparatus with an HAA, and to a manufacturing method of an HAA.
In a magnetic hard disk apparatus, thin-film magnetic head elements for writing magnetic information into and/or reading magnetic information from magnetic disks are in general formed on magnetic head sliders flying in operation above the rotating magnetic disks. The sliders are supported at top end sections of suspensions of HGAs, respectively.
The HGAs are attached to top end sections of actuator arms driven to swing by an actuator or a voice coil motor (VCM) so as to seek a track on a magnetic hard disk. In most cases, a main body of an HAA, which consists of actuator arms and a base section coupled to the arms, is made of a metal material such as an aluminum material in order to reduce a material cost and its weight.
Recent thin-film magnetic head elements, particularly magnetoresistive effect (MR) head elements are more multi-layered and more thinned to increase the recording density, and therefore have extremely weak structure against destruction due to an electrostatic discharge (ESD). Thus, during fabrication and assembling of the HAA and also after installed in a magnetic hard disk apparatus, it is necessary to take more effective countermeasures against the ESD destruction.
One of the effective countermeasures against the ESD destruction is to ground a thin-film magnetic head element to be protected. In this case, how ground the magnetic head element is important. Namely, when the magnetic head element is charged, how dissipates the static electrical charge is very important. This depends on electrical resistances of members arranged along a route of dissipation of the static electrical charge.
If the HAA is made of a good conductive material with a low resistance such as a metal material, the static electrical charge will easily dissipate. However, according to such good conductor material, since current per time becomes large, the magnetic head element will be easily destroyed. Contrary to this, if the HAA is made of an insulation material, the static electrical charge will not dissipate at all causing the amount of static electrical charge to increase. Thus, important is to properly adjust the electrical resistances of members arranged along the route of dissipation of the static electrical charge.
The main body of the HAA, namely the actuator arms and the base section, configures the route of dissipation of the static electrical charge, and is almost made of a metal material. Thus, the resistance of the route of dissipation of the static electrical charge is low and therefore ESD destruction of the thin-film magnetic head elements may easily occur. To solve this problem, it may be consider to change the material of the main body from the metal material such as an aluminum material to other material. However, there is little kind of material to use as the main body of the HAA and thus it is very difficult to find an appropriate material satisfying not only the ESD countermeasures but also the inherent functions of the HAA and the material cost.
It is therefore an object of the present invention to provide an HAA, a disk apparatus with an HAA and a manufacturing method of an HAA, which can dissipate static electrical charge without inducing ESD destruction of the head element even if the same material as the conventional one is used for a main body of the HAA.
According to the present invention, an HAA has at least one HGA, each including a head slider with at least one head element, a suspension for supporting the head slider, and a lead conductor member electrically connected with the at least one head element, and a main body including at least one actuator arm for supporting the at least one HGA. The main body of the HAA is made of a metal material, and a surface of the main body is coated by a diamond-like carbon (DLC) film. A disk apparatus according to the present invention is provided with the aforementioned HAA.
The main body of the HAA, including the actuator arm, is made of a metal material and a DLC film is coated over a surface of the main body. Thus, an electrical resistance of the surface of the main body can be set to a proper value for dissipating static electrical charge to prevent ESD destruction of the head element without modifying the material of the main body. Particularly, since most of the ESD charges flow through the surface of the body, adjustment of a sheet resistance of the surface by the coating of the DLC film is extremely effective as a countermeasures against ESD destruction. As is well known, during the manufacturing and assembling processes of the HAA and also after the HAA is mounted in the disk apparatus, since the main body of the HAA is actually grounded or equivalently grounded by electrically connecting it with a larger volume member, the ESD current will flow through the DLC film coated over the main body of the HAA.
By coating the surface of the main body with the DLC film, fine particles of the metal material can be prevented from flaking off during the assembly process that will be necessarily performed in the assembling process after coating the DLC film. Furthermore, the resistance of the DLC film can be controlled easier than that of a film of a metal oxide material or of a conductive-powder containing resin material. Also, thickness control of the DLC film is easy and therefore the DLC film can be formed in a uniform thickness. Thus, the DLC film can be coated without spoiling the accuracy in size of the main body of the HAA.
It is preferred that the metal material is an aluminum material. Using of the aluminum material for the main body of the HAA presents a low manufacturing cost and also a light weight of the HAA. Also, since the main body is coated by the DLC film, fine aluminum particles can be prevented from flaking off during the assembly process.
Preferably, the DLC film has a sheet resistance in the order of 106 to 1010 xcexa9, more preferably, in the order of 109 xcexa9. Thus, static electrical charge can be effectively dissipated without inviting the ESD destruction.
It is preferred that the assembly further has a coil member of an actuator for driving the at least one actuator arm to swing around an axis.
It is preferred that the at least one head element is a thin-film magnetic head element.
According to the present invention, also, a manufacturing method of an HAA includes a step of preparing at least one HGA, each including a head slider with at least one head element, a suspension for supporting the head slider, and a first lead conductor member electrically connected with the at least one head element, a step of preparing a main body of the HAA, the main body including at least one actuator arm and being made of a metal material, a step of depositing a DLC film to coat a surface of the main body, a step of attaching a second lead conductor member to the main body coated by the DLC film, a step of mounting the at least HGA onto the at least one actuator arm of the main body coated by the DLC film, and a step of electrically connecting the first lead conductor member with the second lead conductor member.
The DLC film is a film developed to realize a composition near to that of a diamond originally. When depositing the DLC film, it is possible to control the binding state between carbons from a diamond state to a graphite state by adjusting process conditions. As is known, the diamond is an insulator whereas the graphite is a conductor. Thus, it is easy to keep a composition ratio of them at a desired constant value by controlling the deposition conditions resulting easy management of the resistance value of the DLC film. Also, thickness control of the DLC film is easy and therefore the DLC film can be formed in a uniform thickness. Thus, the DLC film can be coated without spoiling the accuracy in size of the main body of the HAA. Furthermore, by coating the surface of the main body with the DLC film, fine particles of the metal material can be prevented from flaking off during the assembly process that will be necessarily performed in the assembling process after coating the DLC film.
It is preferred that the metal material is an aluminum material.
Preferably, the depositing step includes depositing a diamond-like carbon film to coat a surface of the main body under a deposition condition for forming the DLC film with a sheet resistance in the order of 106 to 1010 xcexa9, more preferably in the order of 109 xcexa9.
It is preferred that the depositing step includes depositing a DLC film to coat a surface of the main body by a plasma chemical vapor deposition (CVD), an ionization assisted deposition or a sputtering.
It is also preferred that the DLC film is made of a material with a composition of CH, CHN or CHSi.
It is preferred that the method further includes a step of attaching a coil member of an actuator to the main body. The coil member attaching step is executed after the depositing step but before the second lead conductor member attaching step.
It is further preferred that the method further includes a step of attaching a bearing member to an axis of the main body. The bearing member attaching step is executed after the coil member attaching step.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.